Adding beginner's example on using PD15 in OrangePi 3

examples/pd15.c

@@ -0,0 +1,63 @@
+#include <wiringPi.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+
+#if 0
+ +------+-----+----------+------+---+   OPi 3  +---+------+----------+-----+------+
+ | GPIO | wPi |   Name   | Mode | V | Physical | V | Mode | Name     | wPi | GPIO |
+ +------+-----+----------+------+---+----++----+---+------+----------+-----+------+
+ |      |     |     3.3V |      |   |  1 || 2  |   |      | 5V       |     |      |
+ |  122 |   0 |    SDA.0 |  OFF | 0 |  3 || 4  |   |      | 5V       |     |      |
+ |  121 |   1 |    SCL.0 |  OFF | 0 |  5 || 6  |   |      | GND      |     |      |
+ |  118 |   2 |    PWM.0 |  OFF | 0 |  7 || 8  | 0 | OFF  | PL02     | 3   | 354  |
+ |      |     |      GND |      |   |  9 || 10 | 0 | OFF  | PL03     | 4   | 355  |
+ |  120 |   5 |    RXD.3 | ALT4 | 0 | 11 || 12 | 0 | OFF  | PD18     | 6   | 114  |
+ |  119 |   7 |    TXD.3 | ALT4 | 0 | 13 || 14 |   |      | GND      |     |      |
+ |  362 |   8 |     PL10 |  OFF | 0 | 15 || 16 | 0 | OFF  | PD15     | 9   | 111  |
+ |      |     |     3.3V |      |   | 17 || 18 | 0 | OFF  | PD16     | 10  | 112  |
+ |  229 |  11 |   MOSI.1 | ALT2 | 0 | 19 || 20 |   |      | GND      |     |      |
+ |  230 |  12 |   MISO.1 | ALT2 | 0 | 21 || 22 | 0 | OFF  | PD21     | 13  | 117  |
+ |  228 |  14 |   SCLK.1 | ALT2 | 0 | 23 || 24 | 0 | ALT2 | CE.1     | 15  | 227  |
+ |      |     |      GND |      |   | 25 || 26 | 0 | OFF  | PL08     | 16  | 360  |
+ +------+-----+----------+------+---+----++----+---+------+----------+-----+------+
+ | GPIO | wPi |   Name   | Mode | V | Physical | V | Mode | Name     | wPi | GPIO |
+ +------+-----+----------+------+---+   OPi 3  +---+------+----------+-----+------+
+#endif
+
+#define PD15_PIN 9
+
+static void usage(const char* argv0)
+{
+	printf("Usage: %s <on|off>\n", argv0);
+	exit(1);
+}
+
+int main(int argc, char* argv[])
+{
+	printf ("OrangePi Pi wiringPi PD15 test program\n");
+
+	if (argc != 2) usage(argv[0]);
+
+	int mode = 0;
+	if (!strcmp(argv[1], "on"))
+		mode = HIGH;
+	else if (!strcmp(argv[1], "off"))
+		mode = LOW;
+	else
+		usage(argv[0]);
+
+	if (wiringPiSetup() == -1)
+	{
+		fprintf(stderr, "Error setting up wiringPi\n");
+		return -1;
+	}
+
+	pinMode(PD15_PIN, OUTPUT);
+	digitalWrite(PD15_PIN, mode);
+
+	return 0;
+}
+